Circuit Description

1.RECEIVER

The signal from the antenna is passed through a transmission/reception selector circuit and is

amplified by T217. The signal after amplified enter to 1846 for processing then output the audio, the

audio signal is amplified by UTC2822 and output by the speaker at last.

AN

TW

1846

U231

UTC2822

U351 SP

.

T271

ANT

Figure1. RECEIVER CIRCUIT

2.TRANSMITTER

The signal from the microphone passes through 1846, after modulation in the carrier

modulation, the modulation signal with the carrier promotes by buffer T121,T131, and amplified by

T141 then sends to the antenna terminals.

MIC

1846

U231

MIC

T121 T131

T141

.

.

ANT

T423

Figure2.TRANSMITTER CIRCUIT

ANI

T271 U231 U351 SP

ANTSW 1846 UTC2822

1846

T121 T131

T141

T423

MIC

U231

ANI

MIC

3.TRANSMISSION/RECEPTION SELECTOR CIRCUIT

The transmission output is passed through the transmission/reception selector circuit and

low-pass filter to the antenna. The transmission/reception selector circuit, which consists of diodes

D161, D160, D261 and D262, is turned on during transmission and off during reception to switch

the signal.

4.DIGITAL CONTROL CIRCUIT

SIDE KEY AND ENCODER CIRCUIT

The signal from side key and encoder is directly input to the processor.

Reset and backup circuit

When turn on the power, a positive pulse is output from the reset circuit consisting of D831,

C831 and R831 to the third feed of reset terminal on U821 microprocessor. When turn off the power,

U517 detects a 3.3 V drop, and output a low signal, it outputs data to U811 and enter backup mode.

Figure3，digital control circuit

BATTERY VOLTAGE TEST CIRCUIT

Power supply voltage after partial pressure input to the microprocessor analog interface

BATTERY SAVE CIRCUIT

The squelch is off during receive. The power circuit enters battery save mode if no key has

been pressed for five seconds.The circuit is controlled by microprocessor directly.

5.1846 DESCRIPTION

MAINLY SECTION DESCRIPTION

1.DSP consists of IF amplifier, FM modulation, RSSI calculator, AFC control circuit, audio/audio

mixer filter, CTCSS/DCS filter and so on.

2.Synthesizer mainly functions：

1 The synthesizer produces a local oscillator signal, used to switch the RF input to a

continuous low medium frequency.

2 Synthesizer provides the base clock to adjust the VCO frequency.

3.BASE CLOCK

1846 ports more base clocks, for example, 12.8 MHz,13MHz and so on.

4.SERIAL CONTROL INTERFACE

A three lines serial control interface is used to read the main IC and 1846 control record. Serial

control is 24 characters in length, 18 bit numeric string and 6 bit address string.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

A

B

C

D

E

151413121110987654321

E

D

C

B

A

L1550R

C413224P

R4264K7

32

54

1

JK281ST-114

MIC281MICC282

104P

32

54

1

JK351ST-3013-06

AVDD 1

SCLK2SDIO3AVDD4

XTAL15XTAL26

MODE7SENB8

AFO

UT

9N

C10

MIC

_IN

11C

c12

AV

DD

13N

C14

RFI

N15

AV

DD

16

NC 17RFOUT 18NC 19NC 20AVDD 21PABIAS 22AVDD 23PDN 24

GP

IO7/

VO

X25

GP

IO6/

SQ

26G

PIO

5/TX

ON

27G

PIO

4/R

XO

N28

GP

IO3/

SD

O29

GP

IO2/

INT

30G

PIO

1/C

OD

E_I

O31

GP

IO0/

CS

S_I

O32

U231RDA1846

R25812K

L26322NH

C265470P

C3552K2

C26218P

L27522nH

E351220uF

T111NC

T1212SC3356

T141HE0009T131

HE3078

R114NC

R1120R

R115NC

R1161K5

R12110R

R122NC

R1230R

R124NC

R118330R

R119

3K9

R128100K

R12747K

R12647R

R13410P

R14147K

R14247K

R14347R

R159270R

R160270R

C113NC

C115470P

L113NC

C1160R

L11815NH

L117390NH

C117102P

C118102P

C121470P

C12233P

C124470P

C125NC

L1250R

C126NC

C127102P

C128104P

L131101T

C133102P

L1330.4/1.5/4T

L1352.2NHC135

0R

C13420P

C142470P L146

8T(0415)

L143101T

C146470P

C147103P

C148104P

C131103P C143

1uFC144103P

C151NC

C15310P

C15422P

C159100P

C156NC

L160220NH

C160470P

D160HVC131

C16112P

C162470P

C1643P

C1633P

C1662P

C1656P

C1683P5

C1674P

C1691P

L1644T(0410)

L1665T(0410)

L1685T(0410)

L16910K

ANT160ANT-2

R1040.33

R1050.33R1060.33

R170150K

R171150K

R172150K

R173150K

R174150KR175

150K

R17710K

R181220K

R18247K

R1831M

R185180K

R186

33K

C173470P

C172NC

C174103P

C175100P

C176102P

C180470P

C181103P

C182105P

C183102P

2

31

84

U170ALM2904V

76

5

U170BLM2904V

T171DTC114EE

E1804.7uF

BATT3T

3T

3T

C141470P

(T.Y.)

L2614T(0412)

C913103P

C911104P

E91310uF/6V

E91110uF/10V

BATT

R1570.31*1.2*2T

C1575P

C158NC

C114104P

D261HSC277

C2612P

D262HSC277

R35310R

C901105P

L901101T

BATTi

C903470P

BATT

BA

TT

BATT

SW351ARD810S

BA901BATTERY

D161HVC131

R146NC

R113NC

C904103P

C905104P

R814

10K

R877220R

R8751.5K

C876102P

C878102P

A0 1A1 2

GND 4DA5 CK6 A2 3WP7 Vcc8

U81124C08

D875LED(R)

D877LED(G)

T875DTC114EE

T877DTC114EE

C281220P

C841470P

R8454K7

R84647K

SP351SP-1

SW841CALL

R871100K

R87251K

R87310K

C872104P

C811104P

J8BATT

C906470P

C907470P

C136NC

C13215P

C145470P

C90210uF/10V

C284104P

R283

1K8

R284

470R

C2834.7uF/16V

XOUT 3

VC15C4

GND 2

CR22526MHz

C236104P

C235104P

C239103P

C427105P

C258104P

C23010uF/6V

C23210P

C23810P

C237102P

C233104P

L231101T

C231105P

T3512SA1362

T352DTC114EE C352

102P

R3521K

R35147K

C353102P

E3531uF/10V

C351104P

C103103P

R1022K2C102

470P

T1012SB624

R10147K

C101104P

3V3

3V3

BA

TT

i

SP+

MICAFAF i

TX

DR

XD

MIC

AF

AF

i

3V3BATTi

TXDRXDMICAFAF i

3V3BATTi

TXDRXDMICAF

3V3BATTi

TXDRXD

AF

P_AMPAPC

BATTi

TXDRXD

P_AMPAPC

APC

3V33V3

BA

TT

i

RD

A_P

DN

CH

OR

D_S

CLK

RD

A_S

CLK

/PT

T

P_TX

RDA_SCLK/PTT

TXD

BATTiBATTiBATTi

R35533K

R35910R

E3561uF

C356103P

C359104P

C104102P

T102DTC114EE

3V3

3V3

in

Gndout

U911CE6201A33P

R187

10K

C278104P

C858470P

C852470P

C854470P

C856470P

R852100R

R854100R R856

100R

R858100R

R85747K

R85547K

R85347K

R85147K

321

SW851ASW-6

654

C825103P

C823102P

C822103P

C82912P

C82812P CR828

32.768KHz

L821101T

C831102P

C845470P

SW845PTT

C843470P

SW843MONI

R8414K7

R8434K7

R84247K

R84447K

CH2CH1

CH3CH4

CH

2C

H1

CH

3C

H4

P_A

MP

RX

D

AP

C

AP

C

RDA_SDIO/CALL

TX_LED

RX_LED

BATDET

MONI/BEEP

PTT

RDA_INT

RD

A_S

Q

RD

A_C

SS

IN/O

UT

APC

3V3

P_AMP

3V3

RV22150K

C2631P L262

NC

C2754P

T276DTA114YE

P_RX

3V3

R222

22K

C22610P

C221103P

O11

VCC2

GND4 2IN- 52IN+ 6O23

IN+ 7

IN- 8

U351UTC2822

R35710R

C357104P

R35810R

C358104P

C354273P

T2713SK318

C266104P

C271102P

C274470P

C276470P

R267100K

R271220R

L276101T

L27233nH

R268100K

R269100K

C272NCC273

NC

R2661M

R272330R

L1960R

C191

0R

L1930R

C1980R

C193NC

C194NCC195

NC

C192NC

C196NC

C197NC

C223NC

C22

40R

3V3

C360NC

C227103P

R22747K

C279NC

R23910K

C253104P

R25382K

R2554K7

OS

CI

1

OS

CO

2

RE

SE

T3

P5_

04

P5_

15

P5_

26

P5_

37

P5_

48

P5_

59

P5_

610

P6_

011

P6_

112

P6_

213

P6_

314

P6_

415

P6_

516

P6_

617

P6_

718

VS

S19

VD

D20

VC

C21

P7_

022

P7_

123

P7_

224

P7_

325

P7_

426

P7_

527

P7_

628

U821SMP418U1D-110426001

C23410PB

AT

DE

T

R8474K7C847

470PSW847ALARM

R84847K

TX_LED

ALARM

C821104P

C255472P

R2544K7

C254472P

MONI/BEEP

R1842K2

T181DTA114YE

T1822SK1824

3V3

RD

A_SD

IO/C

ALL

MO

NI/

BE

EP

RX

D

TX

_LE

D

RX_LED

ALA

RM

RD

A_C

SS

IN

/OU

T

RDA_CSS IN/OUT

RDA_PDN

RDA_SQ

RD

A_C

OD

E I

N/O

UT

RDA_SCLK/PTT

RDA_INT

RD

A_S

DIO

/CA

LL

RDA_PDN

RDA_SQ

TX

D

P_AMP

RD

A_C

OD

E I

N/O

UT

RD

A_S

DIO

/CA

LL

BA

TT

iP

_AM

PA

PC

3V3

TX

D

3T 3T 3T 3T3TTX_P TX_P

TX_P

RD

A_C

OD

E IN

/OU

T

R235NC

C277102P

T277DTC114EE

C240NC

C270104P

3V3

3V3

RDA_SCLK/PTT RDA_SCLK/PTT RDA_SCLK/PTT

PTT

RD

A_S

CLK

/PT

T

TXD

RXD

SP-

R83810K

R836100R

RDA_SCLK/PTT

R83510K

C15022P

R4551M

T451MRF497

D454KDS122

C455104P

C454104P

R454

470K C452105P

R4511K

C451104P

R452100R

C456470P

3V3

MIC

VO

X_D

ET

VO

X_D

ET

VOX_DET

VO

X_D

ET

T423KTC4082(HF)

MIC

C426NCR427

102P

R425220R

R4182K2

R417

100K R4228K2

C425102P

C419104P

3T

R837100R

R83110K

R832NC

T831NC

C832NC

Out1

VDD2 NC 3

GND 4

U833R3111Q271A

D833NC

C833NC

C155NC

C294470P

T294DTC114EE

R2922K2

R2911KR294

47K

R293100K

C295470P

R295

4K7

T2912SB624

R296100K

C293NC

R297

10KC292470P

C152NC

T8332SK1824

R8341K

R83347K

R514510R C515

103PR51556K

CH

OR

D_S

CLK

NU1VDD2COUT 3VDD4

CBC 5CLK6

DATA7NU8 GND 9NU 10NU 11NU 12VDD 13NU 14NU 15NU 16

U511AUDIO-16

R513330K

C514104P

R5111K

R5121K

C51

110

4P

E352NC

R23

6

0R

Block Diagram

MO

NI

PGA

0/90LN

A

IPGA

Q

DSP

Core

Audio

filterSub

CH

filterFMm

odemA

FCloop

IAD

C

QAD

C

DA

C

AD

C

PA_drvier

LDO

Synthesize

GPIO

Interface

Bus

RSSI

MC

U

INT/G

PIO1

SQ/G

PIO2

PDN

VO

X/G

PIO3

SENSCLKSD

IOC

TSINC

TSOU

T

PA

AN

TSW LD

F

AN

T

DV

DD

AVD

D3．

3VLD

O

+-

ENC

OD

ER

LIMITER

AM

PH

PFPTTPTT

LAM

P

MIC

AF

AM

P

Benchmark

frequencyinput

RFO

UT

VC

O+-

MODEL speficition qty

0P5 C0402 1 C2735P C0402 3 C263 C275 C27210P C0402 5 C232 C226 C234 C191 C23812P C0402 2 C829 C82815P C0402 2 C261 C13227P C0402 2 C262 C13433P C0402 1 C122100P C0402 1 C175102P C0402 19 C878 C876 C425 C353 C352 C183

C277 C831 C823 C271 C237 C176C135 C133 C127 C118 C117 C104R427

103P C0402 15 C515 C913 C356 C239 C825 C822C227 C221 C147 C144 C131 C181C103 C904 C174

104P C0402 29 C511 C911 C359 C358 C357 C455C454 C451 C419 C514 C351 C278C233 C821 C235 C266 C258 C236C148 C128 C114 C253 C872 C811C284 C101 C905 C270 C282

105P C0402 3 C452 C427 C182220P C0402 1 C281224P C0402 1 C413470P C0402 28 C907 C906 C858 C856 C854 C852

C845 C843 C841 C456 C276 C265C160 C274 C146 C145 C142 C141C124 C121 C180 C173 C102 C294C295 C847 C292 C903

472P C0402 2 C255 C254473P C0402 1 C3543P C0603 1 C1636P C0603 1 C16910P C0603 1 C16413P C0603 2 C168 C16622P C0603 1 C16730P C0603 1 C16533P C0603 1 C16156P C0603 1 C15468P C0603 1 C159105P C0603 2 C231 C901470P C0603 1 C162

10uF/10V(106P) C0805 4 C902 E913 E911 C2301uF(105P) C0805 2 C143 E353

4.7uF(475P) C0805 2 E180 C2831uF EIA3216 1 E356

220uF E-06424L 1 E351

0R R0402 7 R123 R112 C224 C198 C116 C115R236

1K R0402 6 R511 R834 R352 R451 R291 R5121K5 R0402 2 R116 R8751K8 R0402 1 R2832K2 R0402 3 R102 R292 C355

capacitanceposition number

BOM

resistance

3K9 R0402 1 R1194K7 R0402 8 R295 R845 R841 R843 R255 R254

R847 R4268K2 R0402 1 R42210K R0402 10 R239 R831 R838 R187 R177 R873

R814 R835 R297 R18410R R0402 5 R359 R358 R357 R353 R12112K R0402 1 R25822K R0402 1 R22233K R0402 2 R355 R18647K R0402 17 R833 R351 R842 R857 R855 R853

R851 R294 R227 R142 R141 R127R848 R846 R844 R182 R101

47R R0402 2 R143 R12651K R0402 1 R87256K R0402 1 R51582K R0402 1 R253100K R0402 8 R293 R296 R269 R268 R267 R128

R871 R417100R R0402 7 R837 R858 R856 R854 R852 R452

R836150K R0402 6 R175 R174 R173 R172 R171 R170180K R0402 1 R185220K R0402 1 R181220R R0402 2 R425 R877270R R0402 2 R160 R159330K R0402 1 R513330R R0402 3 R272 R271 R118470K R0402 1 R454470R R0402 1 R284510R R0402 1 R514680R R0402 1 R4181M R0402 3 R455 R266 R1830R R0603 4 R134 L196 L193 L1250R R0805 1 R15710K R1206 1 L1690.39 R1206 3 R106 R105 R10450K RV1208 1 RV221

27NH L0603 2 L262 L135100NH L0603 3 L118 L263 L275220nH L0603 2 L272 L160390NH L0603 1 L117101T L0603 3 L276 L821 L231101T L0805 3 L143 L131 L901

0.4*1.5*5T 5T 2 L133 L1640.4*1.5*6T 6T 3 L261 L168 L1660.4*1.5*8T 8T 1 L1460.4*1.2*3T 3T 1 L155

LED(G) D0603 1 D877LED(R) D0603 1 D875HSC277 D-ESC 2 D262 D261HVC131 D-ESC 2 D161 D160KDS122 D-USM-MA742 1 D454

RQA0009 T-2N1A-2SK3476 1 T141

induction

diode

audion

2SK1824 T-ESM-2SK1824 2 T833 T182DTA114YE T-ESM-DTA114EE 2 T276 T181DTC114EE T-ESM-DTA114EE 7 T877 T875 T352 T277 T102 T294

T1713078 T-SOT89-2SK3078 1 T131

2SA1362 T-TSM-2SB624 1 T3512SB624 T-TSM-2SB624 2 T291 T1012SC3356 T-TSM-2SC3356(R25) 1 T121

R311Q271A T-US4 1 U8333SK318 T-US4-3SK318 1 T271MRF497 T-USM-MRF497 1 T451

KTC4082(HF) T-USM-MRF497 1 T423

RDA1846 U-QFN32(RDA1846) 1 U231AUDIO-16 U-SOIC16 1 U511

SMP418V1D-110428001 U-SOP28 1 U82124C08 U-SOP8 1 U811

UTC2822 U-SOP8 1 U351HT7333 U-SOT89-5A 1 U911

LM2904V U-SSOP8 1 U170

26MHz FX-DS0305 1 CR22532.768KHz FX-DS0603 1 CR828BATTERY JK-C BC-47S-13-D 1 BA901

SP-1 JP2-SM1.27-3 1 SP351PTT S-SKRT-1 1 SW845CALL S-SS208GS16 1 SW841MONI S-SS208GS16 1 SW843BATT J-TEST POINT 1 J8

ANT-2 PX-333-ANT 1 ANT160MIC MIC98 1 MIC281

SW-6 S-ED08C21O 1 SW851RD810S S-R087FENS 1 SW351ST-114 JK-ST-106 1 JK281

ST-3013-06 JK-ST-3013-06 1 JK351ALARM S-SKHLLBA010 1 SW847

CW50801-03 1

pinouts

PCB

integration

other

Pin No. Pin Name Function description

1 OSCIClock crystal input pin

2 OCSOClock crystal output pin

3 RESERReset pin

4 ALARMAlarm key detection pin

5 RXD read and write frequency data

6 RDA_SDIL/CALL RDA SDIL and CALL key control pin

7 RDA_CEDE IN/OUT 1846 data input/output pin

8 RDA_CSS IN/OUT 1846 CTCSS input/output pin

9 MONI/BEEP squelch key/beep control pin

10 CH4 encoder control pin

11 CH3 encoder control pin

12 CH2 encoder control pin

13 CH1 encoder control pin

14 TX_LED transmit indicator light

15 RDA_INT 1846 data control pin

16 RX_LED receive indicator light

17 TXD read and write frequency data

18 PTT PTT key control pin

19 VSS ground pin

20 VDD power

21 VCC

22 APC auto power control

23 RDA_SCLK/PTT 1846 data control pin

24 BATDET power detection pin

25 RDA_SEN 1846 data control pin

26 RDA_PDN 1846 data control pin

27 VOX-DET VOX detection pin

28 RDA_SQ squelch control pin

Chip Pin Description

Frequency Range 400-470MHz

Channel Number 16

Channel Step 12.5KHz

Antenna Impedance 50Ω

Microphone Impedance 2KΩ

work voltage 7.4V DC

Frequency Stability ±2.5×10-6ppm

carrier output power ≤5W

modulation sensitivity 8-12mV

Modulation Distortion ≤5%

Modulation Limited ≤5KHz

Adjacent Channel Power ≥65dB

Intermodulatohn Rejection ≥40dB

Sensitivity≤0.224uV

Audio Distortion ≤5%

SN RATE ≤-40

Co-Channel Rejection ≥-8dB

Blocking ≥85dB

Adjacent Channel Selectivity ≥55dB

Spurious Radiation ≥55dB

Transmitter

RECEIVER

SPECIFICATION